Method of coating a suction box cover with an organodisiloxane

ABSTRACT

NEW ORGANODISILOXANE COMPOUNDS REPRESENTED BY THE STRUCTURAL FORMULA:   (R1-SI(-O-R2)2)2-O   WHERE R1 IS AN ALKYL RADICAL HAVING BETWEEN 11 AND 30 CARBON ATOMS AND R2 IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF: METHYL, ETHYL, PROPYL AND ISOPROPYL RADICALS. A METHOD FOR APPLYING THE DISILOXANE COMPOUNDS TO SUCTION BOX COVERS INCLUDES THE STEPS OF DISTRIBUTING AN ORGANIC SOLVENT HAVING THE ORGANODISILOXANE DISSOLVED THEREIN OVER THE SUCTION BOX COVER AND EVAPORATING THE SOLVENT.

United States Patent U.S. Cl. 117-99 3 Claims ABSTRACT OF THE DISCLOSURE New organodisiloxane compounds represented by the structural formula:

where R is an alkyl radical having between 11 and 30 carbon atoms and R is a radical selected from the group consisting of: methyl, ethyl, propyl and isopropyl radicals. A method for applying the disiloxane compounds to suction box covers includes the steps of distributing an organic solvent having the organodisiloxane dissolved therein over the suction box cover and evaporating the solvent.

This invention relates to chemistry, and more particularly to novel organodisiloxane compounds and a method of applying such organodisiloxane compounds to suction box covers.

1n the manufacture of paper by use of a Fourdrinier machine, the paperstock, containing approximately 99 /2 water, is discharged onto a continuous wire through which the water will flow. As the wire advances, it will pass over a series of suction boxes fitted with foraminous covers which engage and support the wire. The suction boxes, as the name implies, serve to withdraw water from the pulp mat on the wire. During the manufacture of certain types of paper, solid aluminum resinates, formed during the alum precipitation of resin from the pulp, will form on suction box covers provided with wear resistant surfaces such as those having silicon carbide or titanium carbide surfaces. These aluminum resinates, or pitch, build up on the suction box cover plugging the holes in the cover thereby reducing the efiiciency of the vacuum system. The resinates will also damage the Fourdrinier wire and shorten its useful life.

At the present time highly alkaline chelating compositions are used to remove the resinates, though efforts have been made to treat the suction box covers with a nonsilicone coating in an effort to prevent or minimize deposition of the resinates.

The invention may be generally described as new organodisiloxane compounds represented by the structural formula:

where R; is an alkyl radical having between 11 and 30 carbon atoms and R is a radical selected from the group consisting of: methyl, ethyl, propyl and isopropyl. The invention is also directed to the method of applying the organodisiloxane compounds to suction box covers, which include the steps of distributing an organic solvent having the organodisiloxane dissolved therein on the suction box cover and evaporating the solvent.

For a more complete understanding, reference is made to the following examples, Example I of which describes 3,574,670 Patented Apr. 13, 1971 a manner by which the compounds of the present invention may be produced, and Example II of which describes a method for applying the organodisiloxane to suction box covers.

EXAMPLE I Into a flask fitted with a stirrer were introduced Il-C gH37Sl(OC2H5) (2.14 moles), H O (1.07 moles) and 7 drops of hydrochloric acid which served to catalyze a reaction, which may be represented by the following equation:

The contents of the flask were heated to an initial temperature of 108 and stirring commenced. At the end of a 30 minute period, the temperature had dropped to 82 C. and the stirring was terminated as the contents of the flask appeared homogeneous. After permitting the contents of the flask to stand overnight, the ethyl alcohol was removed therefrom by vacuum evaporation. Specifically, the contents of the flask were heated to a temperature of 212 C. at a pressure of .005 mm. Hg, and the distillate of 97.5 grams collected. The residue in the flask was filtered and permitted to cool.

Analysis of the residue revealed that it 'had a melting point of 4042 C., as determined on a Fisher-Johns melting point block, a refractive index (n at 45 C. of 1.4326, a density (d at 45 C. of 0.8684. The specific refractivity (R of the compound was 0.3012 which corresponded very closely with the calculated specific refractivity of 0.3013. The specific refractivity of the compound:

in Vogel et al., J. Chem. Soc. 514 (1952) and Vogel et aL, J. Phys. Chem, 58, 174 (1954).

EXAMPLE II The compound of Example -I was applied to suction box covers having a silicon carbide surface by preparing a toluene solution which contained 20 percent, by weight, of the 1,3-di-n-octadecyl l,1,3,3-tetraethoxydisiloxane prepared in Example I.

The toluene solution was then sprayed onto several suction box covers and permitted to air dry. The covers were coated with approximately 0.014 gram of the organodisiloxane per square inch.

The suction box covers were then used in a conventional Fourdrinier machine and no appreciable build-up of resinate could be observed after 40 days of use. That quantity of the resinates which did collect on the covers near the end of the test period was considerably less than was observed for untreated covers. Moreover, the treated covers could be more easily cleaned by the use of a high pressure (70 p.s.i.g.) water stream directed against the covers than could untreated covers. With the method of this invention, a new coating can be applied to the suction box covers each time the Fourdrinier wire is changed, usually every 14 to 21 days, or less frequently if resinates have not yet begun to form on the suction box cover at the time a Fourdrinier wire is changed.

the

preparation and use of a particular organodisiloxane represented by the structural formula: OR2 R2 R;Sli0Si-Rr 0R2 0R2 0mg) where R is an alkyl radical having 11 to 30 carbon i) 0 (Ri) atoms and R is a radical selected from the group C(32) 0mg) consisting of methyl, ethyl, propyl and isopropyl;

and

evaporating the organic solvent. 2. The method of claim 1, wherein the disiloxane comother compounds may be prepared by the reaction de- Pound 1S1 scribed in Example I. For example, R may represent any 0C2H OC2H alkyl radical having more than 11 and less than 30 car- 15 bon atoms, and R may represent a methyl, propyl or O-CzH OC2H5 isopropyl radical as well as an ethyl radical.

Care should be exercised in preparation of the organodisiloxanes of the present invention to provide only enough water in the reaction described in Example I to hydrolyze one of the al-koxy groups on the organo-silicon starting material, as organodisiloxane yield will decrease significantly if excess Water is present.

While rather specific terms have been used to describe one embodiment of the present invention, they are not intended, nor should they be construed as a limitation box distributing over the surface of the suction box cover an organic solvent having dissolved therein a disiloxane compound represented by the structural formula 3. The method of claim 1, wherein the organic solvent is toluene.

References Cited UNITED STATES PATENTS 2,917,530 12/1959 Bailey 260-448.8X 3,048,499 8/1962 Jellinek 260-448.8X 3,262,842 7/1966 Justus 162-374 3,436,306 4/1969 Haberecht et al 162374 ALFRED L. LEAVITT, Primary Examiner E. G. WHITBY, Assistant Examiner US. Cl. X.R. 

